ITO (indium-tin oxide) has been widely used as a current diffusion layer in fabrication of an LED (light emitting diode) device. To achieve a light extraction efficiency enhancement, a commonly used method is to roughen the surface of an ITO layer. In the prior art, the method for roughening the surface of the ITO layer mainly comprises a dry etching method and a wet etching method. A dry etching method may comprise steps of forming the ITO layer, forming a pattern using a photoresist, and etching an ITO region which is not protected by the photoresist using ICP (inductive couple plasmas), so as to roughen the surface of the ITO layer. A wet etching method may comprise steps of coating a layer of nanoparticles on at least a portion of surface of the ITO layer as a protective layer and etching a region which is not covered by the nanoparticles using a corrosion solution, such as an acid solution, so as to roughen the surface of the ITO layer.